U.S. President Barack Obama told defense officials from some 20 countries October 14 that he is deeply concerned about the Islamic State (IS) group's siege of the Syrian town of Kobani and that the United States would keep launching air strikes in the area.

Obama said he is also concerned about the IS push in Iraq's western Anbar province, which the Iraqi military risks losing completely to the jihadists.

Obama was addressing the defense officials at the start of a meeting at the Andrews Air Force Base outside Washington.

The U.S.-led coalition faces pressure to halt the advance of the militant group, which made gains in Anbar and in Kobani, on the Turkish border.

The U.S. president said a total of some 60 countries have joined the anti-IS effort, but he predicted a "long-term campaign" against IS and declared the U.S. and allied goal is to destroy IS so it no longer represents a threat in the region or to the world.

But he cautioned that the campaign will include progress and setbacks.

Prior to the meeting, the U.S. military said a U.S.-led international coalition carried out 21 air strikes against IS militants in and around the besieged northern Syrian town of Kobani on October 13 and 14.

U.S. Central Command said it was the most strikes carried out by the coalition in Syria since it began its air campaign against IS militants there.

Defense officials from Turkey were also present at the meeting, as were Arab nations that have joined the United States in launching air strikes against the militants in Syria, such as Saudi Arabia and the United Arab Emirates.

The White House earlier on October 14 said the meeting, led by General Martin Dempsey, chairman of the Joint Chiefs of Staff, was "part of ongoing efforts to build the coalition and integrate the capabilities of each country into the broader strategy."

Colonel Ed Thomas, Dempsey's spokesman, said no major policy decisions were expected, adding: "It's about coming together in person to discuss the vision, the challenges, the way ahead."

Obama announced on September 17 that the United States and its partners would "degrade and ultimately destroy" the Islamic State militant group "through a comprehensive and sustained counterterrorism strategy."

IS militants control one-third of Kobani, which is bordered by Turkey on the north and surrounded by fighters on the south, east, and west.

Iraq’s Kurdistan regional government says it has provided military assistance to Kurdish forces in Kobani.

But Kobani Defense Council chief Esmat al-Sheikh said no weapons or ammunition have been received there.

A Syrian Kurdish military official said the shipment was stuck in northeast Syria because Turkey refuses to open a transit corridor to Kobani.